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A068090 Numbers n which divide the right concatenation of the first n even numbers. 0
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 14, 15, 18, 20, 24, 25, 30, 35, 36, 39, 40, 45, 50, 60, 72, 75, 80, 90, 100, 120, 125, 144, 150, 180, 200, 204, 225, 240, 250, 300, 360, 375, 400, 450, 500, 507, 540, 585, 600, 624 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..49.

EXAMPLE

The right concatenation of the first six even numbers is 24681012 and 6 divides this number. So 6 is a member of the sequence.

MAPLE

a := proc(n): if n=1 then RETURN(2) fi: 2*n+a(n-1)*10^(ceil(log[10](2*n+.01))) end: for n from 1 to 1000 do if a(n) mod n = 0 then printf(`%d, `, n) fi; od:

MATHEMATICA

concat[n_]:=FromDigits[Flatten[IntegerDigits/@Range[2, 2n, 2]]]; Select[ Range[700], Divisible[concat[#], #]&] (* Harvey P. Dale, Nov 02 2011 *)

CROSSREFS

Cf. A029455.

Sequence in context: A248888 A112587 A141820 * A172121 A094222 A164043

Adjacent sequences:  A068087 A068088 A068089 * A068091 A068092 A068093

KEYWORD

base,easy,nonn

AUTHOR

Amarnath Murthy, Feb 19 2002

EXTENSIONS

Edited and extended by James A. Sellers, Feb 20, 2002

STATUS

approved

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Last modified November 16 17:25 EST 2019. Contains 329201 sequences. (Running on oeis4.)